Biogeographical patterns of arctic-alpine fungi: Distribution analysis of Marasmius epidryas, a typical circumpolar species of cold environments

Abstract

The existence of an arctic-alpine element is well-known in the biogeography and taxonomy of fungi, however synthetic analyses concerning their global distribution, morphological variation and ecology are largely lacking. Here, we compile all available information including published data and herbarium material concerning Marasmius epidryas, a characteristic representative of arctic-alpine macromycetes which grows exclusively on dead woody tissue of Dryas species. Our primary aim was to obtain as complete a picture as possible of the known distribution of an arctic-alpine fungus. Additionally, we attempted to analyse the variation of morphological features, phenology and ecology throughout its range. According to our data, the species has been recorded from over 300 localities. Although the records are clearly biased due to an uneven concentration of mycological investigations, the fungus was found in all parts of its presumable circumpolar distribution outlined by presence of the host plant. The localities included main northern and high-mountain areas as well as peripheral, southernmost parts of the Dryas distribution in Europe (Balkan Mts.), North America (Rocky Mts. of Colorado) and Asia (Altai Mts.). However, it may be a rare species in some regions. Marasmius epidryas appears to occur in most types of vegetation harbouring its host, an important arctic-alpine dwarf shrub, and is noted as a dominant fungal element for some. No significant differences were found in phenology of M. epidryas between the alpine and the arctic sites, with most records in August. Similarly, although there is a significant variation in quantitative morphological characters, no particular geographical trends were detected. © 2010 Pacific Northwest Fungi Project.